The assemblage represents a significant design change in masonry units such as to help generously in meeting current demands for improved energy-efficient building components.
Present day concerns relative to energy conservation have dictated the development of improved techniques for incorporating integral thermal insulation in buildings and other structures of single wythe masonry walls.
Walls have heretofore been insulated to be sure, sometimes by applying layers of thermally insulative material to the exterior formed wall surfaces in the effort to meet the required thermal insulation standards. But these solutions have required additional protective covering adding appreciably to the construction and maintenance costs and loss of the durability of the concrete for permanence purposes.
Too, insulation in some form is sometimes introduced to the block cavities after a course thereof has been laid. In some instances, the system has envisioned the placement of insulative material in the cores or air cells between the outer and inner block walls while ignoring completely the thermal throughpaths represented in the webs of the blocks extending in planes normal to those outer and inner walls, and/or the thermal paths represented in the end areas of the blocks outboard of the outermost webs, all seriously limiting the achievable thermal insulative effects.
The standard concrete block must be understood to define two primary heat paths; those extending from the outside to the inside face shell through the outside and inside walls and through the core or cores, and those extending from the outside to the inside face shell through the outside and inside walls and through the webs connecting therebetween.
Heretofore, it has been believed necessary only to insulate the core area or areas in order to satisfy the demands of builders and owners and to meet the requirements of codes, all in the striving for thermally efficient exterior envelopes.
But those stark facts of modern life, higher fuel costs and need for energy conservation, not to mention increasingly greater stringencies in developing code requirements, all have dictated a need for new solutions in product design and thermal transmission values.
Given the general acceptance of a single wythe load-bearing masonry wall as one of the most economical approaches to appealing design of buildings, while most effectively off-setting spiraling construction costs and satisfying code specifications, this invention gives significant answer to the vexing problem of heat flow through the conventional masonry unit by the introduction of what I elect to define as an engineered air gap which creates a thermal break in the novel web of my design.
A prime consideration in the development of my design has been toward a maximizing of the block's thermally insulative quality, while yet maintaining its structural integrity through increased web thickness to provide the necessary strength and rigidity for withstanding vertical and eccentric loading and to meet fire ratings as determined by equivalent thicknesses.
Other key considerations have been in lessening significantly the thermal conductivity by interrupting to as great a degree as possible the thermally conducting through paths offered by the webs and by the retention of cavities for the normal handling and installation techniques incorporating any of the various types of horizontal and wall reinforcing wires and ties.
Another consideration has been to provide a thermally insulated masonry block requiring only a single unitary elongated insulative liner within the block confines, which liner may be installed at the manufacturing site wherefor the composite structure can be pelletized and transported to the construction site by the normal and conventional methods.
Before now, buildings have been insulated in a plurality of different ways, each system presenting problems of its own, with the generally accepted objection to the techniques so far developed being that the insulating member is usually brought to the construction site as a separate member, there to be integrated with a related building block, usually following the laying of each course of blocks as the wall structure undergoes erection. The known techniques do not lend themselves to the obviously desirable fact situation of combining block and filler, as it is sometimes called, at the situs where the block is cast and then transporting the so-modified block to the construction site whereat the mason need only lay up same according to his conventional techniques, the need for any adding filler to block after the block has been set in place, with the added labor costs represented thereby, being obviously obviated.
The systems of the prior art are exemplified in the pertinent U.S. Pat Nos. of which I am aware and include:
Parreton: 3,204,381 of Sept. 7, 1965 PA0 Grants: 3,318,062 of May 9, 1967 PA0 Moog: 3,410,044 of Nov. 12, 1968 PA0 Perreton: 3,546,833 of Dec. 15, 1970 PA0 Whittey: 3,885,363 of May 27, 1975 PA0 Nickerson: 4,027,445 of June 7, 1977 PA0 Warren: 4,071,989 of Feb. 7, 1978 PA0 Warren: 4,073,111 of Feb. 14, 1978
Many of these citations have included proposals involving the placement of a thermal insulation medium within a concrete block, as for example as exemplified in U.S. Pat. Nos. 2,199,112, 2,852,934, 3,204,381, 3,318,062, 3,546,833, and 3,885,363, but most proposals suffer from the obvious disadvantage that the preformed insulative liners have to be set in place with respect to the preformed blocks only after the blocks have been laid in situ, the procedure normally taking place following the laying of each course, when the laying of blocks momentarily stops and placement of liners ensues, an utter waste of time and money.
In some prior art instances, the system envisions the placement of insulative material in the air cells between the outer and inner block walls, all the while ignoring completely the thermal throughpaths represented in the webs of the blocks extending in planes normal to the outer and inner walls and in the end cores created when blocks are placed end-to-end, thereby seriously limiting the achievable thermal insulative effects.
In Perreton, U.S. Pat. No. 3,204,381, when and where, as he indicates, the insulating member may be provided as a strip of any desired length to be received in a plurality of blocks, it is obvious that such strip could only be added to the plurality of blocks after the blocks are set in place. While it is true that he states that the insulating member can be inserted in the block prior to laying the same in a wall, he does describe and illustrate an insert which has one side offset longitudinally and vertically for shiplapping purposes wherewith he effects an interlocking situation. Obviously, with parts of the insert extending outwardly of a side or face of the block, the combination of block and insert does not lend itself to a favorable stacking situation in the transport of the supplies to the construction site. And this is equally true of Perreton, U.S. Pat. No. 3,546,833.
Incidentally, neither Perreton block allows any extending through the cores thereof of piping or wiring or cement, once installed, and all for the obvious deleterious reason that the entirety of the core is filled with insulating material.
Many different types of insulated building blocks have bee proposed and utilized, and are exemplified in the patent literature, but with many of such, they merely provide air spaces for insulation purposes. In many other cases, where the provided air spaces are large enough to accomplish an insulating function, the load-carrying characteristics of the block have been infringed upon.
Another common difficulty with the prior art mechanisms has been that, while a barrier wall may be extended through the air space or spaces in a block, no provision is made for extending that barrier wall through the usual block webs at the sides of the air spaces.
The geometry of the block of this invention allows a mold design such that, in the forming process, the area within the mold and below the web air gaps may be filled by conventional vibration and compaction techniques at normal cycle speeds for maximum production and, without the need for additional bottom sled plates or special rakes.
Further advantageously, tests performed on conventional blocks and on the blocks hereof have disclosed comparative compressive strengths and greatly improved thermal resistance values.